Ingham



(No Model.)

0. L. BUCKINGHAM- BESTAVAILABLE COP ELBGTRIQ ARC LAMP.

N0. 3Z0 ,841. Patented June 23, 1885.

WITNESSES: INVEN TOR N. PE ERS. mmmmmr. waun im DJ.

BEST AVAILABLE COP.

UNITED STATES PATENT OFFICE.

CHARLES L. BUOKINGHAM, on NEW YORK, n. Y.

ELECTRIC-ARC LAMP.

EPECIFICATION forming part of Letters Patent No. 320,841, dated June 23,1885. Application filed August 26,. 18554. (No model.)

To all whom it may concern:

Be it known that I, CHARLES L. BUCK- INGHAM, of the city, county, and'State'of New York, a citizen of the United States of America, have madea new and useful. Improvement in Electric-Arc Lamps, of which thefollowing is a specification.

My invention is an improvement in that class of lamps in which, first,an electro-magnet in the arc-branch primarily separates the carbons toestablish an arc, and then causes the lilting-clutch to release thecarbon-holder, leaving it suspended by a second and independent support;second, the feeding of the carbons is controlled by a second andshuntbrancli electro-magnet. In lamps of this particular class, as wellas those in general in which the arc is established by an arcbrancheleetro-magnet, it often occurs that, while the current is flowing infull strength through said electro-magnet, the carbonholder slipsthrough its lifting-clutch, thus permitting the carbons to come togetherwhile the lifting-clutch is in its extreme upward position. It isobvious that it is then incapacitated from lifting the carbon-holder. toreestablish the are. To re-establish the are it would be necessaryeither for an attendant to go to the lamp and manually separate thecarbon points, or else that the current on the line be temporarilysuspended, thereby permitting the clutch to fall to its lowest position.The clutch when in its lowest position is assumed to be capable ofestablishing an are upon a resumption of current.

The object of my invention is to enable an arc to be instantaneouslyreestablished at any time, in the event of an accidental slippingtogether of the carbon points, while a current of full strength isflowing over the are-branch. To this end I employ a shunt of lowresistance around the arc-branch electromagnet, and said shunt is openedand closed through the agency of an electro-magnet which is included inthe fine-wire shuntbranch. This shunt-branch electro-inagnet is adaptedto attract its armature at the moment an arc of normal length isestablished, and long before the electro-magnet in the same shunt-branchis actuated to feed the carbons together. W'ith such an arrangement itis to be observed that the current passing through the arc-brancheleetro-magnot primarily separates the carbon points and establishes anare; that at the moment the arc is established enough current will flowthrough the fine-wire shunt to cause one of its electro-magnets to closea short circuit around the are-branch electromagnet, thereby deprivingsaid arc-branch electro-magnet of enough current to retain thelifting-clutch in a position of suspension; that upon theshort-cireuiting of the arc-branch electromagnet the liftingclut-ch isreleased and falls to its lowest position, ready to again grasp andraise the carbon-holder upon the breaking of the short circuit aroundthe arc. \Vhile a normal current is flowing through the arcbranch,enough current, at the same time, is flowing through the fine-wire shuntto cause the electro-magnet therein, above mentioned, to retain theshunt around the arc-bran ch electro-magnet closed; but in the event ofthe slipping together of the carbon points the arc-branch resistance isgreatly reduced, and the current upon the high-resistance shuntbranch isso far reduced as to permit the shunt-branch electrounagnet to break theshort circuit of the arc-branch electromagnet, thereby causinga strongcurrent to again flow through the latter clcetro-magnet and toreestablish the are.

In my lamp the carbon-holder ishcld between rollers whose pressure is soadjusted that, when uninfluenced by either the lifting or feedingelectro-magnet, said carbon-holder will be stationarily suspendedbetween the rollers or any suitable friction-support.

To establish an are between the carbons, the arc-branch electro-inagnetis capable of lifting a carbon-holder against the action of thepressurerollers or friction su iports, and likewise to effect a feed.The influence of the liftingmagnet having first been removed, the feed-5 ing electro-magnet is capable of forcing the carbon-holder in anopposite and downward direction against the action of thepressure-rollers or friction-support.

I will now describe my invention by refer- ICO ence to the accompanyingdrawing.

F is a carbon-holder, which is raised to pcsition to establish an arebetween C G byrollers against the action of gravity.

When the carbons are in contact, as they normally are, an arc isestablished by a main-line current first passing through the coils ofthe arc-branch electro-magnet A, whereby the hollow axial armature B israised, and its liftingt-oe C lifts one side of the ring-clutch until itclutches and raises the'carbon-holder, and until the opposite side ofthe ring is arrested by, an adjustable stop, E. The main line curent isdivided at point a over two branchesone including electro-magnet A andthe lightgiving carbons, the other a high -resistance shun t, :2, aroundthe are, which embraces feeding eleetro-magnet G and short-circuitingelectro-magnet Hand reunites with the main circuit at w. When, now, acurrent isfirst sent to line, the arc is immediately established, and,when of a normal length, enough current is diverted to the shunt-branchto cause electromagnet H to attract its armature o from its backcontact, 12, to its front contact, y, thereby elosin g a short circuitwhich begins and terminates at s and r of the arc-branch around thecoils of A. When armature 0 is thus attracted, nearly the entire currentof the arc-branch isdiverted from the coils of A, and armature B and thering-clutch at once fall to their lowest posit-ion, thereby releasingthe lifting-clutch from the carbon-holder and leaving it supported, withthe are intact,wholly through the agency of clampingrollers I) c. Armatnre owill remain attracted and the coils of A short-circuited as long asthe arc resistance continues. normally great. or throughother accidentthe carbons should. be brought so close together as to greatly di-' If,however, by an overfeed minish the arc-resistance, nearly the entirecurrent of the shunt-branch would be diverted, and therebyelectro-magnet H would release its armature 0, thus breaking the shortcircuit of A. The breaking of said short circuit will again result in astrong current in the coils of A, and the lifting-clutch will again bebrought into operation and the carbon-holder lifted until the arc hasattained its normal length.

Although clamping-rollers b c are adequate to support the carbon-holderagainst the action of gravity, the carbon-holder is readily given anupward movement by means of the lifting-magnet A, and adownward movementby means of a positive feeding apparatus. The feeding of a carbon-holderis effected through a differential electromagnet, G, having twooppositely-wound coils, j and 7c, the first of which is normally closed,while the latter is normally open between anvil Z and circuit-closingarm at, which is attached to armature-lever g. The two branches beginand terminate at o and w. When only a normal arc-resistance exists, notenough current is flowing in the shunt to cause G, through coil j, toattract its armature, and in that case the armature-lever g, pivoted ath, is held in a retracted position by spring a, and the clam ping-toe iis in its extreme upward position, and is not in contact with thecarboirholder. If, however, owing to the consumption of the carbons, orfor any other reason, the arc-resistance should become abnormally high,the current in coil j of G will attract its armature, and t will clutchthe carbon-holder and thrust it downward a small fraction of an inch,and until an and I come in contact. hen in and Z make contact, a currentis set up in 7a, and the effects of the two equal coils become neutraland the armature is retracted. After being retracted, if enough currentremain in the shunt-branch to again attract the armature of G, of coursethe carbon-holder will be fed a second step, and the step-by-stepfeeding will continue until an ample feed of the carbons has occurred.

At all times when enough current is flowing in the shunt to actuate thefeeding devices, armature 0 will remain attracted and Ashort-circuited;but 0 will also be attracted and A short-circuited long before thefeeding devices will be operated. Although 0 should be attracted'by aweak current in the shunt, it should not be attracted before an arc isestablished. To render the movement of 0 slow, a dash-pot, or anywell-known form of retarding device, may be employed.

What I claim,and desire to secure by Letters Patent, is

1. In an electric lamp, the combination of a lifting eleetro-magnet forestablishing an are, a clamping apparatus for supporting the carbonagainst the action of gravity which is independent of the lifting andfeeding apparatus, and a second electro-niagnet and feeding apparatuswhich are independent of the lifting and supporting devices.

2. In an electric lamp, the combination of an arc-branch electro-magnet,a shunt-branch electro-magnet which is called into action when thenormal are is established, and a clutch for establishing the are throughthe agency of the arebranch electro -magnct, which clutch is unlockedfrom the carbon holder and returned to its normal position under thecontrol of the shunt electro-magnet, and which remains in readiness toreestablish the are in case of an overfeeding of the carbonholder.

8. In an electric lamp, the combination of a clutch and mechanism forcausing the clutch to first lift the carbon apparatus, to then. causethe clutch to release the carbon, and to imme- IIO dinteiyiei'urn snidclutch toaposition to again ed to lift and release the carbon and to berelii't said carbon upon an abnormal diminution oi arc-resistance.

4. In an electric-121111 the combination of a lifting eleotro-niagnetand a clutch, a short circuit for said lifting eleotro-magnet, and ashunt eiectro-mngnet for opening and closing sm' d shortoii'cuit,whereby the clutch is adaptturned to its original position upon theostnb- 1o lishment of a normal are.

CHARLES L. BUOKINGHAM.

Witnesses:

J OHN D. VAN HORNE, WILLARD BROWN.

